Unventilated Roof Construction

It is generally formed by using eaves ventilators and ridge or abutment ventilators.

Unventilated roof construction.

Roofing panels can get wet when design or construction flaws allow moisture in when ice dams damage shingles or when strong winds and storms damage the roofing. Vapour permeable underlays are used on sloping roofs with areas covered by non permeable materials e g. Decreases air leakage infiltration. A breather membrane for pitched roofing is defined by bs 5250 2002 as a one that has a water vapour resistance figure of less than 0 25 mns g.

In flat roof construction thermal insulation can be placed above and below the structural roof deck or waterproofing layer. In addition to warm hybrid and cold roofs applications include scottish sarking board systems low pitched metal roofs and wall and floor applications. Ventilation is required to the underside of the deck. Controls airflow ccspf is air impermeable adheres well to almost all construction surfaces and expands to fill voids creating an air seal and eliminating air leakage.

For designers the advantage of using unventilated construction comes from removing the necessity to provide a ventilated cavity below the sarking. This cold deck construction is considered problematic in the humid temperate climate of the uk where the effective. Tyvek supro does not need any soffit tile or ridge ventilation which can save time and money in the construction process. Wet roofing panels have even less of a chance of drying in an unventilated attic when insulation has been applied directly to the underside of the roofing panels.

Benefits of sealed warm roofs. Unvented roof assemblies with ccspf work well in all climate zones and serve several important functions. Hot roofs can create a stack effect this is because the attic space will be under positive pressure and this can the lower living space of the home to be under negative pressure which forces.

Also available with integral tape dupont tyvek supro plus. This is known as a fully ventilated airspace as opposed to an unventilated air space. In cold climates it prevents warm humid indoor air from reaching. No ventilation to roof space required.

This allows for air to enter in one opening and exit the other forming a cross flow of ventilation. Roof space unventilated and sealed. When placed below the structural deck. Thermal insulation following the rafter line.

Minimises the thermal bridge at the eaves. Unventilated cold roofs have insulation placed over a horizontal ceiling and a vapour permeable underlay type lr is used.